mirror of
https://github.com/xiaoqidun/ofdgo.git
synced 2026-10-29 17:27:08 +08:00
88 lines
2.5 KiB
Go
88 lines
2.5 KiB
Go
// Copyright 2025-2026 肖其顿 (XIAO QI DUN)
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package geom
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import (
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"math"
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)
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// ConvexContains 判断单个非退化凸直线区域是否包含另一闭合直线区域
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// 入参: outer 外部区域, inner 内部区域
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// 返回: bool 是否完全包含，曲线及多轮廓返回false
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func ConvexContains(outer, inner Path) bool {
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a, b := geometryPolygonPoints(outer), geometryPolygonPoints(inner)
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if len(a) < 3 || len(b) < 3 {
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return false
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}
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nondegenerate := false
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for i, start := range a {
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end := a[(i+1)%len(a)]
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dx, dy := end.X-start.X, end.Y-start.Y
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length := math.Hypot(dx, dy)
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if !finite(length) {
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return false
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}
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if length == 0 {
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continue
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}
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dx, dy = dx/length, dy/length
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distance := func(point Point) float64 {
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x, y := point.X-start.X, point.Y-start.Y
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value := math.FMA(dx, y, -dy*x)
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bound := (math.Abs(dx*y) + math.Abs(dy*x) + math.Abs(dx)*(math.Abs(point.Y)+math.Abs(start.Y)) + math.Abs(dy)*(math.Abs(point.X)+math.Abs(start.X))) * 0x1p-49
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if finite(bound) && math.Abs(value) <= bound {
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return 0
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}
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return value
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}
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sign := 0.0
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for _, point := range a {
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value := distance(point)
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if !finite(value) || sign*value < 0 {
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return false
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}
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if value != 0 {
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sign, nondegenerate = math.Copysign(1, value), true
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}
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}
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for _, point := range b {
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value := distance(point)
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if !finite(value) || sign*value < 0 {
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return false
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}
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}
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}
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return nondegenerate
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}
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// geometryPolygonPoints 读取单个显式闭合直线轮廓的顶点，不修改原路径
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// 入参: path 直线轮廓
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// 返回: []Point 独立顶点，其他路径返回nil
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func geometryPolygonPoints(path Path) []Point {
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if len(path) < 4 || path[0].Verb != Move || path[len(path)-1].Verb != ClosePath {
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return nil
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}
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for i, segment := range path[:len(path)-1] {
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if i > 0 && segment.Verb != Line || !finite(segment.End.X) || !finite(segment.End.Y) {
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return nil
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}
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}
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points := make([]Point, len(path)-1)
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for i := range points {
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points[i] = path[i].End
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}
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return points
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}
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